 /*******************************************************************************
  * Copyright (c) 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.texteditor;

 import java.util.ArrayList ;
 import java.util.List ;

 import org.eclipse.core.runtime.Assert;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.core.runtime.Status;

 import org.eclipse.ui.internal.texteditor.NLSUtility;
 import org.eclipse.ui.internal.texteditor.TextEditorPlugin;

 /**
  * Describes a contribution to the 'org.eclipse.ui.workbench.texteditor.hyperlinkDetectorTargets'
  * extension point.
  *
  * @since 3.3
  */
 public final class HyperlinkDetectorTargetDescriptor {

     private static final String HYPERLINK_DETECTOR_TARGETS_EXTENSION_POINT= "org.eclipse.ui.workbench.texteditor.hyperlinkDetectorTargets"; //$NON-NLS-1$
 private static final String TARGET_ELEMENT= "target"; //$NON-NLS-1$
 private static final String ID_ATTRIBUTE= "id"; //$NON-NLS-1$
 private static final String NAME_ATTRIBUTE= "name"; //$NON-NLS-1$
 private static final String DESCRIPTION_ATTRIBUTE= "description"; //$NON-NLS-1$
 private static final String CONTEXT_ELEMENT= "context"; //$NON-NLS-1$
 private static final String TYPE_ATTRIBUTE= "type"; //$NON-NLS-1$

     private IConfigurationElement fElement;


     /**
      * Returns descriptors for all hyperlink detector extensions.
      *
      * @return an array with the contributed hyperlink detectors
      */
     public static HyperlinkDetectorTargetDescriptor[] getContributedHyperlinkDetectorTargets() {
         IExtensionRegistry registry= Platform.getExtensionRegistry();
         IConfigurationElement[] elements= registry.getConfigurationElementsFor(HYPERLINK_DETECTOR_TARGETS_EXTENSION_POINT);
         HyperlinkDetectorTargetDescriptor[] hyperlinkDetectorDescs= createDescriptors(elements);
         return hyperlinkDetectorDescs;
     }

     /**
      * Creates a new descriptor from the given configuration element.
      *
      * @param element the configuration element
      */
     private HyperlinkDetectorTargetDescriptor(IConfigurationElement element) {
         Assert.isNotNull(element);
         fElement= element;
     }

     //---- XML Attribute accessors ---------------------------------------------

     /**
      * Returns the hyperlink detector target's id.
      *
      * @return the hyperlink detector target's id
      */
     public String getId() {
         return fElement.getAttribute(ID_ATTRIBUTE);
     }

     /**
      * Returns the hyperlink detector target's name.
      *
      * @return the hyperlink detector target's name
      */
     public String getName() {
         return fElement.getAttribute(NAME_ATTRIBUTE);
     }
     
     /**
      * Returns the types that the context of this
      * hyperlink detector target supports.
      *
      * @return an array with type names that this target's context supports
      */
     public String [] getTypes() {
         IConfigurationElement[] contexts= fElement.getChildren(CONTEXT_ELEMENT);
         String [] types= new String [contexts.length];
         for (int i= 0; i < contexts.length; i++)
             types[i]= contexts[i].getAttribute(TYPE_ATTRIBUTE);
         return types;
     }

     /**
      * Returns the hyperlink detector target's description.
      *
      * @return the hyperlink detector target's description or <code>null</code> if not provided
      */
     public String getDescription() {
         return fElement.getAttribute(DESCRIPTION_ATTRIBUTE);
     }


     public boolean equals(Object obj) {
         if (obj == null || !obj.getClass().equals(this.getClass()) || getId() == null)
             return false;
         return getId().equals(((HyperlinkDetectorTargetDescriptor)obj).getId());
     }

     public int hashCode() {
         return getId().hashCode();
     }

     private static HyperlinkDetectorTargetDescriptor[] createDescriptors(IConfigurationElement[] elements) {
         List result= new ArrayList (elements.length);
         for (int i= 0; i < elements.length; i++) {
             IConfigurationElement element= elements[i];
             if (TARGET_ELEMENT.equals(element.getName())) {
                 HyperlinkDetectorTargetDescriptor desc= new HyperlinkDetectorTargetDescriptor(element);
                 if (desc.isValid())
                     result.add(desc);
                 else {
                     String message= NLSUtility.format(EditorMessages.Editor_error_HyperlinkDetectorTarget_invalidExtension_message, new String [] {desc.getId(), element.getContributor().getName()});
                     TextEditorPlugin.getDefault().getLog().log(new Status(IStatus.ERROR, TextEditorPlugin.PLUGIN_ID, IStatus.OK, message, null));
                 }
             } else {
                 String message= NLSUtility.format(EditorMessages.Editor_error_HyperlinkDetectorTarget_invalidElementName_message, new String [] { element.getContributor().getName(), element.getName() });
                 TextEditorPlugin.getDefault().getLog().log(new Status(IStatus.ERROR, TextEditorPlugin.PLUGIN_ID, IStatus.OK, message, null));
             }
             
         }
         return (HyperlinkDetectorTargetDescriptor[])result.toArray(new HyperlinkDetectorTargetDescriptor[result.size()]);
     }
     
     private boolean isValid() {
         return getId() != null && getName() != null;
     }

 }

